Carburetor idle fuel control



June 7, 1966 B. WALKER ETAL 3,254,638

CARBURETOR IDLE FUEL CONTROL Filed Aug. 27, 1952 5 Sheets-Sheet l N 28 F 2 g 0 1 26 I 1/ 7 p 332 35 32 O 492'. g

INVENTORS BROOKS WALKER FRANK W. KERTELL June 7, 1966 B. WALKER ETAL CARBURETOR IDLE FUEL CONTROL 5 Sheets-Sheet 2 Filed Aug- 27, 1962 INVENTORS 32 BROOKS WALKER BYFRANK W. KERTELL 4 MM ATTORNEY June 7, 1966 B. WALKER ETAL 3,

CARBURETOR IDLE FUEL CONTROL 50 .5'0 INVENTOR.

I BROOKS WALKER Q I 0 FRANK m KR7LL Q I l 0 g loo 6 AT TORNEY.

United States Patent 3,254,638 CARBURETOR IDLE FUEL CONTROL Brooks Walker, '1280 Columbia Ave., San Francisco,

and Frank W. Kertell, Oakland, Calif.; said Kertell'assignor to said Walker Filed Aug. 27, 1962, Ser. No. 219,475 11 Claims. (Cl. 123-97) This invention pertains to a cam controlled idle fuel circuit and other features listed herein.

This means of control of the idle circuit was purposely designed to eliminate the electrical means of control, thus eliminating more sources of trouble in respect to the service and servicing of the needed idle fuel control unit to be adapted for improved smog control.

The mechanical means of control also affords a less costly unit in its manufacture. This is an important factor in the invention. A control of this invention could use the Walker hydraulic governor as discussed in US. application Serial No. 140,632, filed on September 18, 1961, and now abandoned, entitled Governor? This Walker hydraulic control as utilized here does not actuate any electrical switches but generates a full mechanical movement that actuates a quick dropping and quick raising cam against an arm bearing a cam roller mounted upon one end of said arm to partially rotate a shaft that is relieved so that two balls can sit on respective ball seats and block off any flow of idle fuel or gases from entering the engine manifold or allowing the idle fuel circuit to supply idle fuel.

Another feature of this invention is that when the unrelieved portion of the shaft is so rotated that it lifts the balls from their seats, fuel is allowed to flow to the idle jets and manifold, thus letting the idle circuit function for engine idle and limited power from the idle fuel.

Another feature of the invention is that the cam, namely a throttle cam, is used in conjunction with the governor cam'although working independently of the governor cam. The throttle cam is linked to the throttle arm and receives a partial rotation with a partial rotation of the throttle shaft.

Another feature of this invention is that when the throttle is cracked from its idle position, the cam connected by a link immediately lifts the idle control arm, thus allowing the idle fuel circuit to be open for delivery of idle fuel to the intake manifold. As the engine speed increases, the governor controls its respective cam to close the idle circuit or lower the idle control arm and partially rotate the cam shaft that would normally close off the fuel supply but the throttlecam is overriding and full fuel flow in the idle circuit is in effect for engine idle and limited power from the idle fuel.

Another feature of the invention is that should the throttle be closed quickly at above predetermined engine speeds, as for a level, or closed quickly for a down hill deceleration, the idle circuit will be closed as soon as the throttle dashpot (not shown but common to induction smog controls, such as in US. Patent No. 2,809,623 to F. V. Hall) allows the throttle to become fully closed, while the engine speed is still high or above said predetermined value such as 25 to 32 miles per hour. 1 Below said predetermined speed such as 25 to 32 miles per hour the governor override cam will lift the idle control arm so that fuel will again flow through the idle circuit, thus wetting the engine manifold for power or maintaining idle performance.

Another feature of this invention is that extra fuel is introduced into the manifold to assist in wetting the manifold when the idle fuel is turned on after deceleration by suitable means such as a limited stroke of the accelerator pump. This can be accomplished by a telescoping soft 3,254,638 Patented June 7, 1966 ice link mounted between the throttle arm and accelerating pump arm, this linkage being spring loaded. This spring will yield and allow the accelerating pump to be actuated by the upward or opening movement of the idle control arm that is lifted by the clockwise rotation of the governor cam, this upward move giving a little additional fuel to help wet a dry manifold caused by a long deceleration run.

- Other features of this invention include means for admitting more than the idle fuel to the manifold as the idle fuel is turned on after being shut off on deceleration in a smog controlled'induction system for better come on of engine power to prevent stalling if the engine is to idle after deceleration, as at a stop light.

Another feature is to give better come on of power after deceleration if power to accelerate is desired as in passing slow traflic after a deceleration, etc. by automatically adding more than idle fuel to the intake manifold.

Another feature is the use of the normal accelerator pump to give this extra fuel even if the accelerator is left closed as when coming from a deceleration toan idle as when approaching a stop light, etc.

We have illustrated our invention in the accompanyin g drawings, in which:

FIG. 1 is a side elevation of a curburetor and controls embodying one form of the invention.

FIG. 2 is a side View similar to FIG. 1 but partly cutv away, showing the invention in a different cycle of its operation.

FIG. 3 is a view similar to FIG. 1 and FIG. 2 but partly cut away, showing a still further cycle in its operation. FIG. 4 is an enlarged end view partly in section of one of the ball valves in the idle circuit of the invention shown 7 FIG. 8 is -a side elevation diagonal section through the accelerator pump and center screw of main jet' venturi support carburetor embodying this invention.

FIG. 9 is a plan View of the carburetor shown in FIG. 8

- taken at the parting line 99. v

In all figures like numerals of reference refer to corresponding parts.

We have shown a carburetor 10 attached to an engine manifold 9 having a throttle shaft 11, a throttle shaft control arm 12, a throttle control arm 13 which may be of the soft link type if the carburetor is to be used as a smog control type of device.

An accelerator pump shaft 14 is of a conventional type as shown on pages 243-247, on overhauling Rochester 2gc carburetor in Gleens New Auto Repair Manual 1962.

An antiperculator valve 17 is adapted to be opened by end 16 of accelerator pump arm 15 when the throttle control arm 12 is in the throttle closed or idle position in the conventional manner. Link 18 is pivoted to throttle control arm 12 and telescopes into the hollow portion ofportion 19. Spring 20 is secured at its upper end to pin 22 that pivotally secures link 19 to accelerator arm 15 and the lower end of spring 20 is secured to link 21 that rides on-the turned end 18a of link 18 to pull link 18 into link 19 but allow a sliding extension of the soft link formed by links 18 and 19. Pin 22 rides in slot 24 of link 23. The lower end of link 23 is pivotally secured to the cam arm 25 by pin 26. Cam arm 25 is secured to cam shaft 28. Cam shaft 28 has two cams 29 and 29 formed in it and at each cam is a groove 31 in shaft 28 to allow fuel to pass when the ball valves 30 are lifted slightly off their seats, as shown in FIG. 5.

Roller 27 rides on either of two controlling cams, throttle cam 32 or governor controlled cam 33. Governor controlled cam 33 is pivoted on shaft 37 and secured from sliding off by collar 38. Cam 33 is also pivoted to shaft 37 and actuated by link 39 which is secured to cam 33 by pin 35. Spring 36 urges cam 33 clockwise, as viewed in these figures, and is secured at its lower end in hole 33a and is adjustable in tension by arm 40 which is secured to bracket 42 by screw 41 which is screwed into arm 40 and adjustable in slot 43.

Diaphragm governor actuator 45 has diaphragm 46. The upper side is exposed to the pressure from the Pitot type pick up 52 in the liquid pump 53 by tube 48 while the lower side of the diaphragm is exposed to the pressure on the intake 50 to the pump 53 by tube 49. This makes the action of the diaphragm relatively unaffected by the thermostat or pressure cap that may be used in the radiator and circulating cooling system of a vehicle motor, as explained in said Walker application, Serial No. 140,632 entitled Governor.

Shaft 47 is suitably sealed in actuator housing 45 and is connected to link 39 by pin means.

In actuation when the engine is idling the throttle cam 32 will be in the position shown in FIG. 1 which if alone would allow roller 27 to drop and shut off the idle fuel, as shown in FIG. 4, but spring 36 pulls governor cam 33 to the position shown in FIG. 1 due to the low liquid pressure on Pitot tube 52 over the pressure in tube 49 on the lower side of diaphragm 46. This position of governor cam 33 holds roller 27, as shown in FIG. 1, and holds ball 30 off its seat, as shown in FIGS. 1 and 5. There are two cams 29 and 29' and associated balls similar to 30 on shaft 28 to control dual idle fuel paths in two barrel carburetors, such as as shown in said Chilton Company book Glenns New Auto Repair Manual 1962, pages 234-235, paragraphs 342, 3-44, 345.

As the throttle is opened throttle cam 32 is rotated clockwise by link 54 to hold roller 27 up in idle fuel admitting position, as shown in FIG. 3 and FIG. 5. This is the roller 27 position at cruise above a predetermined engine speed of around 25 to 32 miles per hour and at all accelerations above said 25 to 32 miles per hour.

On deceleration above a predetermined speed, such as 25 to 32 miles per hour, the throttle cam 32 will be in the closed throttle position, as shown in FIG. 2, and the governor cam 33 will be in the position shown in FIG. 2 due to the high pressure on Pitot tube 52 compared to the pressure in tube 49 at the higher engine speeds. These positions of throttle cam 32 and governor cam 33, as shown in FIG. 2, on higher speed deceleration lower roller 27 and close ball valve 30, as shown in FIG. 4, to

close oif the idle fuel on deceleration for reduction in smog producing components of the engine exhaust.

At the end of deceleration, if the throttle is left closed as in approaching a stop light the governor cam 33 will move to the position shown in FIG. 1 at a predetermined speed around 25 to 32 m.p.h. depending on the adjustment of spring 36.

During deceleration, with the idle fuel shut off, as shown in FIG. 2, the intake manifold will be dry or relatively dry of fuel and no combustion will result; but when roller 27 is raised at the predetermined speed, an extra shot of fuel is introduced to help wet the intake manifold by the actuations of the accelerator pump by the counter clockwise partial rotation of accelerator pump control arm by the lifting of arm 23 by arm when roller 27 is raised by governor cam 33, as shown in FIG. 1, from the deceleration idle fuel off position shown in FIG. 2.

In FIGS. 8 and 9 we show the carburetor 10, the throttle shaft 11, the throttle valve 50, the idle fuel orifice 51 controlled by idle fuel adjustment screw 52, transfer port 53 above the upper edge of the closed throttle 50, cam shaft 28 that has cam face 29 and groove 31.

When shaft 28 is rotated partially by the raising of arm 25 through the action of cams 32 and 33 (not shown in FIG. 8) on roller 27, idle fuel will be admitted through tube with bleed port 61 which acts as an anti-Syphon when the engine is stopped. Idle fuel will flow from pipe 60 through port 62 (around vertical port 92), through port 63, and through port 64 past raised ball 30 around groove 31 into ports 65 and 66 past idle needle valve 52 and from idle fuel port 51 into the carburetor barrel below the butterfly 50.

The accelerator pump is actuated by accelerator pump arm 15 which operates shaft 14 passing through the inside of the carburetor where shaft 70 operates piston rod 71 which telescopes into hollow piston support 73 which has a slot 74 and in which a pin 71:: rides. Pin 71a is secured to piston rod 71 and limits the relative motion of hollow piston support 73 relative to piston rod 71. Spring 75 rides on washer 76 at its upper end which is supported onrod 71 by adapter 77. Cup leather 80 is supported between washer 81 and nut 82. Ball 83 and very light spring 84 allow fuel to enter through port 85 from slot 86 in cylinder 87 which is cast integrally. with the bowl of the carburetor which contains fuel 90. Spring 91 urges the cup leather and associated parts to a raised position but spring 75 is much stiffer than spring 91 and can force the cup leather down as the throttle is opened through the action of telescoping rods 18 and 19 when the throttle is opened, or the action of arm 25 and link 23 which provides a partial stroke of the cup leather 80 when the idle fuel is turned on after being shut 013?. A shoulder 87a in the bottom of cylinder 87 abuts against the nut 82 to limit the stroke of the cup leather 80. The linkage with the throttle is such that the full stroke of the cup leather from about the position shown in FIG. 8 to where nut 82 abuts against shoulder 87a will take place in the first part of the opening of the throttle and the last portion of the opening will provide no additional stroke of the accelerator pump as the nut 82 will have abutted against shoulder 91 and spring 75 will then compress for the balance of the partial rotation of accelerator pump arm 15 as controlled by links 18 and 19 to the throttle arm 12.

Fuel to the accelerator pump flows from the fuel in the float bowl through slot 86 through port 85 past ball 83 to the area below the cup leather 80. As the cup is forced down, fuel flows through port 92, port 93, past spring-loaded ball 94, through ports 95 and 96 around bolt 97 and is injected into one of the carburetor barrels through port 98. A similar port injects into the other of a two-barrel carburetor, as shown in FIG. 9. From the injected spray from port 98, and its associated port for the other barrel, the fuel flows down around the essentially closed (but not fueltight) butterfly 50 and the twin butterfly in the other barrel and provides extra fuel to help wet the. manifold when the idle fuel is turned on after decelerating from a higher speed to a lower speed so that the engine Will not stall. When the throttle 50 is opened, the accelerator pump will act in the normal manner ejecting fuel through port 98 past the partially open throttle 50 so that the engine will not stumble when the throttle is opened rapidly. Idle fuel free air can'be admitted through tube 100 and adjusted by screw 101 in the manner described in co-pending application Serial No. 192,873, filed on May 7, 1962, entitled Carburetor Mixture Control, by applicants.

If the throttle is suddenly opened during a deceleration from the position shown in FIG. 2 to the position shown in FIG. 3 at speeds above the predetermined speeds of, say, between 25 and 32 mph, the throttle cam 32 will move from the position shown in FIG. 2 (throttle closed position) to the power position shown in FIG. 3. During such transition, as roller 27 raises the idle fuel on position, the accelerator pump will be given a partial stroke to add fuel to assist in wetting the manifold and get better power take hold. Links 18 and 19 will also gest themselves without departing from the spirit and scope of the invention. The disclosures and description herein are purely illustrative and are not intended to be in any sense limiting.

We claim as our invention:

1. An intake manifold, a carburetor for controlling the combustible mixture to an engine including a throttle valve, an idle fuel passage from the carburetor to said manifold means for automatically shutting off said idle fuel flow through said passage at closed throttle high engine speeddecelerating conditions, an engine speed sensing device automatic means including said speed sensing device for admitting idle fuel through said idle fuel passage below a predetermined engine speed at closed throttle operation and means for simultaneously introducing extra fuel to said manifold by other means as said idle fuel is readmitted to said engine even while said throttle valve remains closed, said speed sending devicebeing independent of the suction in said intake manifold, said means for introducing extra fuel to said manifold also serving to introduce extra fuel when said throttle valve is moved from a part open position to a wide open position.

2. A structure as defined in claim 1 in which said carburetor has an accelerator pump, said extra fuel being supplied by said accelerator pump even if said throttle remains closed, said accelerator pump also being actuated by the opening of said throttle valve, to admit extra fuel to said engine on sudden opening of said throttle valve, from a partly opened position such as a fortymile per hour level cruise position to a fully open throttle position.

3. An engine, including an intake manifold, a carburetor for controlling the combustible mixture to said engine including a throttle valve, a first cam mechanically associated with said throttle valve, an idle fuel circuit, a shut off valve in said circuit, said cam holding said idle fuel shut off valve open when said throttle valve is not in closed position, a second cam, an engine speed sensing device, controls for said second cam that move said second cam to one position at low engine speeds and to another at higher engine speeds, said controls including said speed sensing device, said second cam holding said idle fuel circuit valve open at low engine speeds when said first cam would allow said idle fuel valve to close, a rider riding on both said cams, said shut off valve controlling the flow of idle fuel past said throttle valve, said rider connected to said shut off valve for controlling the flow of said idle fuel, said rider holding said shut off valve open at idle and all open throttle valve positions and closing said shut off valve and flow of idle fuel at some closed throttle valve high engine speed operations.

4. An engine, including an intake manifold, a carburetor for controlling the combustible mixture to said engine including a throttle valve, a first cam mechanically associated with said throttle valve, an idle fuel circuit, a shut off valve in said circuit, said cam holding said idle fuel shutoff valve circuit open when said throttle V valve is not in closed position,'a second cam, an engine speed sensing device, controls for said second cam that move said second cam to one position at low engine.

speeds and'to another at higher engine speeds, said con-' trols including said speed sensing device, said second cam holding said idle fuel circuit valve open at low engine speeds when said first cam would allow said idle fuel valve to close, an accelerator pump associated with said carburetor, automatic means for giving said accelerator pump a partial stroke as said second c'am moves from high engine speed to low engine speed position while said throttle valve is in closed position.

5. A structure as defined in claim 3, a barrel in said carburetor, an orifice through which said idle fuel is admitted to the carburetor barrel automatic means for introducing extra fuel to said manifold as said idle fuel circuit is opened when the engine speed is reduced below a predetermined speed with said throttle valve closed, said extra fuel being admitted through said orifice which is separate from said fuel circuit.-

6. A structure as defined in claim 5, an accelerator fuel pump in said carburetor including a mechanical linkage between said cams and said accelerator pump, said automatic means for introducing extra fuel including motion derived from one or both said cams through said linkage as said cams move from higher engine speed positions to a predetermined lower engine speed at closed throttle operation.

7. A structure as defined in claim 6 in which said extra fuel is controlled by a partial stroke of said carburetor accelerator pump as controlled by said speed sensing device even without motion of said throttle valve from the closed position.

8. A structure as defined in claim- 7, said accelerator pump providing extra fuel as said throttle valve is opened suddenly'at low engine speeds before said second cam has moved to the higher engine speed position.

9. An engine including a carburetor, said carburetor including a throttle valve, an accelerator pump, an idle fuel supply circuit, a system for feeding idle fuel on the engine side of said throttle valve at engine idle conditions through said idle circuit, means for shutting off the flow of said idle fuel during high speed closed throttle decelerations, automatic means for simultaneously giving said accelerating pump a partial stroke when said idle fuel is turned on while said throttle valve remains closed as during decelerations, and means for giving said accelerator pump a partial stroke when the throttle valve is moved from a partiallyopen position to a fully open position.

10. A structure as defined in claim 9, a main induction passage in said carburetor, a valve for controlling the turning on and turning off the flow of said idle fuel through said passage, a mechanical linkage between said valve and said accelerator pump, said linkage providing a partial stroke to. said accelerator pump to inject said extra fuel into said induction passage from said accelerator pump automatically along with the turning on of the idle fuel through said idle fuel passage.

11. An engine including a carburetor, said carburetor accelerator pump coincidental with the turning on of said flow of idle fuel to said engine after said flow of idle fuel has been stopped, said partial stroke of said accelerator pump taking place while said throttlevalve remains in the closed or idle throttle position, separate linkage between said throttle valve and said accelerator pump, said accelerator pump receiving a partial stroke when said throttle valve is opened due to said separate linkage.

References Cited by the Examiner UNITED STATES PATENTS 1,982,049 11/1934 Fageol 123--97 2,036,205 4/1936 Ericson .12397 (Other references on following page) UNITED STATES PATENTS Hoof 12397 Mallory 12397 Mall cry 12397 Leibing 12397 Cornelius 12397 MARK NEWMAN, Primary Examiner.

RICHARD B. WILKINSON, FRED E. ENGEL- THALER, Examiners.

A. L. SMITH, Assistant Examiner. 

9. AN ENGINE INCLUDING A CARBURETOR, SAID CARBURETOR INCLUDING A THROTTLE VALVE, AN ACCELERATOR PUMP, AN IDLE FUEL SUPPLY CIRCUIT, A SYSTEM FOR FEEDING IDLE FUEL ON THE ENGINE SIDE OF SAID THROTTLE VALVE AT ENGINE IDLE CONDITIONS THROUGH SAID IDLE CIRCUIT, MEANS FOR SHUTTING OF THE FLOW OF SAID IDEL FUEL DURING HIGH SPEED CLOSED THROTTLE DECELERATIONS, AUTOMATIC MEANS FOR SIMULTANEOUSLY GIVING SAID ACCELERATING PUMP A PARTIAL STROKE WHEN SAID IDLE FUEL IS TURNED ON WHILE SAID THROTTLE VALVE REMAINS CLOSED AS DURING DECELERATIONS, AND MEANS FOR GIVING SAID ACCELERATOR PUMP A PARTIAL STROKE WHEN THE THROTTLE VALVE IS MOVED FROM A PARTIALLY OPEN POSITION TO A FULLY OPEN POSITION. 